B star

A large, luminous, blue-white star of spectral
type B with a surface temperature of 10,200 to 30,000°C. The spectrum
is characterized by absorption lines of
neutral or singly ionized helium, with lines of atomic hydrogen evident,
especially at the cooler end of the range.

Main sequence B stars, examples of which
include Spica and Regulus,
have a mass in the range 3 to 20 solar masses and a luminosity of 100 to
50,000 times that of the Sun. Often they are found together with O
stars in OB associations since, being
massive, they are short-lived and therefore do not survive long enough to
move far from the place where they were formed. Their brief main sequence
careers, measured in tens of millions of years, probably allows too little
time for even the most primitive forms of life to develop on any worlds
that circle around them (assuming that life could exist at all in such an
environment).

B-type supergiants, of which Rigel
is a familiar example, may be up to 25 times as massive and 250,000 times
as luminous as the Sun.